The invention relates to a collecting cylinder of a folding unit of a printing press and method for operating the same.
Folding units of printing presses are used to form folds in printed substrates, wherein for fold formation, a web-shaped printing substrate is normally first fed through a so-called former in order to form a longitudinal fold on the web-shaped and not yet severed printing substrate. Starting from the former, the web-shaped printing substrate is transported over several draw rollers in the direction of a cutting knife cylinder, whereby copies are severed on the cutting knife cylinder by cross-cutting the web-shaped printing substrate. The copies severed from the web-shaped printing substrate at the cutting knife cylinder are held or carried over by a cylinder cooperating with the cutting knife cylinder, whereby holding devices of this cylinder are designed either as pins or as grippers for the copies being separated from the printing substrate. The cylinder cooperating with the cutting knife cylinder is consequently formed as a function of this either as a pin cylinder or a gripper cylinder. If cross-folds are supposed to be formed on the severed copies, tucker blades are integrated into the pin cylinders or gripper cylinders, which, when the cross-folds are being formed in the copies, also press them between folding jaws of a folding jaw cylinder that is cooperating with the pin cylinder or gripper cylinder. If no cross-folds are supposed to be formed in the copies, no tucker blades are integrated into the pin cylinders or gripper cylinders. The copies severed from the web-shaped printing substrate and provided with cross-folds, as the case may be, can be provided in the area of a folding table with a second longitudinal fold, which runs parallel to the longitudinal fold formed in the former.
The pin cylinder or gripper cylinder cooperating with the cutting knife cylinder can be formed as a so-called collecting cylinder in order to provide the folding apparatus with a collecting function. These types of collecting cylinders make it possible to stack several copies in the area of the collecting cylinder and thus to collect them. Special control of the holding devices and the movement of the tucker blades of the collecting cylinder is required in collect mode as well as in non-collect mode and, as the case may be, of the tucker blades of the collecting cylinder, whereby opening and closing of the holding devices in collect mode is controlled via at least one control cam and at least one cam collect of the collecting cylinder. In non-collect mode, opening and closing of the holding devices and the movement of the tucker blades is controlled exclusively by the control cams.
A collecting cylinder of a folding unit of a printing press is known from German Patent Document DE 38 10 439 C1. Thus, in addition to at least one control cam, the collecting cylinder is comprised of at least one cam collect. In order to transfer the collecting cylinder according to DE 38 10 439 C1 between collect mode and non-collect mode and back, the, or each, cam collect is drivable via a hollow pinion positioned so that it is axially displaceable on a shaft embodied as a worm, whereby the collecting cylinder can be transferred or switched between collecting mode and non-collecting mode and back by axial displacement of the hollow pinion. This type of structural design for the collecting cylinder requires a relatively large construction.
Starting herefrom, the present invention is based on the objective of creating a new type of collecting cylinder of a folding unit of a printing press.
According to the invention, the cylinder body of the collecting cylinder along with the, or each, control cam is positioned via a first bearing body on a frame, wherein the, or each, cam collect is positioned via a second bearing body coxially to the first bearing body on an axis of the collecting cylinder, wherein a speed difference between the, or each, cam collect and the collecting cylinder can be made available via transmission gearing having several gears and a shiftable unique coupling, and wherein, to switch the collecting cylinder between non-collect mode and collect mode and back with an opened unique coupling, an exclusive relative rotation between the, or each, cam collect and the collecting cylinder around a specific angle can be realized in such a way that the unique coupling is also rotatable around this angle.
In the case of the collecting cylinder in accordance with the invention, the transfer between non-collect mode and collect mode and back takes place exclusively via a relative movement between the, or each, cam collect and the collecting cylinder.
In contrast to the prior art according to DE 38 10 439 C1, when transferring the collecting cylinder between non-collect mode and collect mode and back, there is no axial movement of the components of the cylinder, so that the inventive collecting cylinder has a smaller structural shape as compared with the prior art. In addition, the inventive design of a collecting cylinder is structurally simpler and therefore more cost-effective.
Preferred developments of the invention are yielded from the following description. Without being limited hereto, exemplary embodiments of the invention are explained in greater detail on the basis of the drawings.